


Two Weeks

by The_Busy_Beee



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Alpha/Beta/Omega Dynamics, Alternate Universe - Modern Setting, Anal Fingering, Anal Sex, Established Relationship, Fluff and Smut, Knotting, M/M, Mating Cycles/In Heat, Nesting, Overstimulation, Praise Kink, Self Confidence Issues
Language: English
Status: Completed
Published: 2020-12-17
Updated: 2020-12-17
Packaged: 2021-03-11 03:47:06
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,367
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28138665
Author URL: https://archiveofourown.org/users/The_Busy_Beee/pseuds/The_Busy_Beee
Summary: Omega Gen is spending his first heat with his alpha boyfriend Senku. He's worried that Senku will be disillusioned when he sees just how clingy and needy he can be, but Senku doesn't mind at all.Quite the opposite, actually.
Relationships: Asagiri Gen/Ishigami Senkuu
Comments: 18
Kudos: 319





	Two Weeks

**Author's Note:**

> Happy Holidays everyone~! 💞💞
> 
> I hope you all enjoy this fluffy, smutty SenGen~!

"Are you sure you wanna do this?" Senku asks for the third time in as many minutes. 

"I should really be asking you that," Gen laughs, shifting the strap of his duffle bag as they climb the stairs to Senku's apartment. "You're going to have to deal with me for two weeks. Are  _ you _ sure you wanna do this?"

"You say that like you don't practically live at my place anyways," Gen doesn't have to see Senku to know he's smiling behind him. "You might as well just move in on a permanent basis."

"We'll talk about that if we survive my heat." Gen rolls his eyes, amused smile tugging at the corner of his lips. Truthfully, he wouldn't mind moving in with Senku. They've been dating for close to a year now, and it's almost scary how fast and hard they fell for one another, but as cliche as it sounds, once they met, everything seemed to fall into place. What they don't share in common they're polar opposites in, and Gen finds it more than a little amusing. 

He would call them something cheesy like soulmates if it wouldn't make Senku scoff and roll his eyes.

Sometimes Gen spends a week at Senku's apartment, but he never stays much longer than that at a time because Senku is still a student. The alpha always reminds him it's only for another semester, but Gen's been there before, and in his experience, the last year of college is the most stressful. That's part of the reason Gen hasn't invited Senku to share a heat with him- the stress and strain of working and college isn't easy to balance, nor is it easy to get a week's worth of vacation from both when you're part of the research department. But, a greater part has undoubtedly been Gen's anxiety.

Senku is very mature. Gen is the older one in their relationship, if only by three years, and while he lets himself be whiny and needy sometimes, it's only in careful doses. During a heat though, he can't really help it. The week of his heat is usually spent in a haze. There are periods of lucidity in which he chugs water and takes a spit bath, but on the whole, it's hot and painful and when he comes to at the end of the week, he's always uncomfortably sticky and crusty, covered in his own fluids. The week leading up to his heat isn't awful, but he's definitely more clingy, and he's been worried that it might be off putting. 

Senku isn't averse to touches and cuddles, but he's always so cool and composed- Gen just can't seem to let Senku see the part of him that wants to be spoiled. He keeps his omega in check when he's around Senku, but that all changes this week.

It's make or break.

Well. It's probably not  _ that _ serious.

But it's definitely going to be an experience for both of them, and Gen just hopes Senku won't be disillusioned by the end of it. 

\---

They go shopping on Sunday and buy bottles of water and sports drinks to keep in the bedroom, and plenty of fresh fruits and granola bars. Gen won't eat much during the week, but he  _ will _ need to eat  _ something _ to keep his strength up between waves. Gen drops a box of heat aides into the basket as they pass by them, to help with the cramping this week, and Senku reaches for a box of condoms, but Gen shakes his head.

"I'm on birth control~," he sing-songs, continuing down the aisle. The thought of fucking Gen through his heat with no protection is on Senku's mind the rest of the shopping trip and walk home- Gen knows because he can  _ smell _ the low level of arousal on Senku and it makes warmth settle low in his stomach.

He pins Senku against the front door when they get back to his apartment, grocery bags falling to the floor and spilling their contents around them as he kisses Senku fiercely- fists his fingers in Senku's long hair, presses their bodies together, swallows Senku's needy growls.

They jerk each other off in the entryway, panting and groaning into one another's mouths, and while Senku slumps boneless against the front door, Gen takes the food to the kitchen.

He has energy to spare right now. Maybe after he puts everything away, Senku will fuck him in the kitchen.

\---

By Tuesday, all the excess energy Gen was feeling is gone, and now he's just tired.

Senku has been at the college from morning to evening the last couple days, taking care of everything he can in preparation for next week, and Gen misses him. He curls up on the couch in Senku's comforter and sleeps the day away surrounded in the mellow richness of Senku's alpha scent. 

He smells like the forest right after a rainstorm; crisp and a little bitter, but with a hint of something chemical that Gen chalks up to working in the laboratory for so long. It's more than a little soothing, and Gen only gets up twice for snacks. 

When Senku comes home with take out, that's where he finds Gen. The omega wakes up to the sound of take out being pulled out of a plastic bag and peeks over the edge of the comforter, hair ruffled and eyes squinted. Senku is grinning at him.

“Morning, sleepyhead,” he laughs softly. “Looks like you had a nice day.”

“...Is that cake?” Gen asks, eyeing the small cake box on the corner of the coffee table, completely ignoring the spread of dinner food on the small table.

“For after dinner,” Senku deadpans, taking the box with him as he rises to his feet. “I saw the trash. Have you only eaten snack cakes all day??”

“Maybe...” Gen mumbles, bottom lip thrust out in a pout as he tugs the comforter tighter around him. 

“You need a balanced meal,” Senku chastises, returning with a couple bowls and sets of chopsticks. “You won’t last all week if you only eat honey buns and cream bread.”

Gen sighs, slipping down into the floor to sit across from Senku. The alpha watches Gen serve himself, still wrapped in his comforter with an amused smile, waiting until Gen has taken at least a few bites before serving himself as well.

\---

Senku's "vacation" starts on Wednesday, and Gen takes full advantage of it.

He latches himself to Senku like an octopus and doesn't let the alpha go more than three feet without him. They move from the bed to the couch, and the couch to a pile of pillows and blankets on the floor, and Gen watches crappy reality tv shows between naps while Senku does his schoolwork online. He rests his head on Senku's thigh, and the alpha combs his fingers through Gen's hair distractedly, and it's so soothing that Gen has to wonder why he's never allowed himself to do this before.

When Senku gets up to go to the bathroom, Gen starts to get up as well, only to be stopped by Senku's outstretched hand.

"Stay," he orders, lips pursed. Gen blinks, surprised.

"Why?"

"Following me around the apartment is fine. Hanging off my shoulders while I make food I can handle- but we're not going to the bathroom together."

"I could-"

"You're not gonna wait in the hall," Senku frowns. "I'll be five minutes, tops. Just wait for me-" he pauses, licks his lips, and Gen can practically see the gears turning in that perfect head of his, "wait for me here like a good boy."

Oh.

Oh, Gen likes that very much.

He smiles up at the alpha, flutters his lashes. "Yes, Senku-chan."

\---

On Thursday, Gen nests.

He feels the pull, the itch, the  _ heat _ beginning to simmer just under his skin. 

Gen forces Senku out of the bedroom as soon as the alpha wakes, still bleary eyed and groggy, and refuses to let him in until after he’s perfected their nest. He collects all the pillows and blankets he can find, and holes himself up in Senku’s bedroom most of the day, only coming out for lunch and dinner. Senku doesn’t comment, choosing instead to work on his schoolwork as he listens to Gen fuss over his nest. 

Senku had never seen a nesting omega, but he’s read up on it. 

He’s done everything possible to make sure Gen’s heat with him is the best he’s ever had- he even bought a bunch of new blankets to wash in his own laundry soap and slept with them the previous week. He’s heard the closet door open and shut in the bedroom, so Senku is certain Gen must have found them, but he knows he won’t be allowed to see the nest until Gen deems it ready.

He’s antsy, though.

He wants to see it.

He wants to wallow in their combined scents alongside Gen.

Gen had warned Senku that he’d be clingy this week, and Senku thought he was prepared for it, but he was absolutely unprepared for how Gen being needy and clingy would affect  _ him. _

Senku isn't a typical alpha, by any means.

He's not usually territorial, nor is he possessive or argumentative. He doesn't dote on his omega like most alphas would, and he's sure most people would assume them a beta/beta couple until they catch their scents. 

He didn't think he'd enjoy a “typical” omega, couldn't even imagine dating someone like Luna or Ruri, but Gen...

Gen wanting to be pampered and spoiled is a different story.

Something about Gen  _ allowing _ Senku to see this side of him has warmth bubbling in his chest and heat simmering low in his abdomen. Senku blinks, tries to set those thoughts aside for now, but his fingers hover over the keys of his laptop, brain unable to focus.

He hasn’t written a word in nearly two hours.

The sound of the bedroom door opening has Senku’s head snapping up and heart soaring into his throat. He stares at the mouth of the hallway, watching, waiting. When Gen finally peeks around the corner, he looks a little sheepish. His cheeks are filled with color, but Senku isn’t sure if that’s from the preheat or embarrassment. He rolls his lips between his teeth for a second before clearing his throat.

“I think I'm done, so… would you come see my nest, Senku-chan?”

Senku nearly trips over his own feet in his haste to follow Gen to the bedroom. 

Instead of attempting to build his nest on Senku's bed, Gen has stripped the full size comforter off the bed and made his nest between the wall and Senku's side of the bed. It's smaller than Senku's bed, but not uncomfortably cramped; all of Senku's and Gen's blankets have been tucked in and around the edges, making for a comfortable barrier between their bodies and the wall and Senku's bedframe. Soft pillows lay at the head of the nest, in front of the nightstand, and shirts and pants have been tucked in around the pillows and blankets as added cushioning.

_ Senku's  _ shirts and pants.

Senku swallows as he catches a whiff of their combined scents. 

Gen’s floral scent is getting sweeter, taking on thicker, honied notes. Senku can feel an anticipatory buzz under his skin. 

The air feels charged.

“So?” Gen asks, sitting down in the center of the nest and pulling one of the small pillows into his lap, clutching it to his chest. He somehow manages to look confident and nervous all at once. Senku smiles and tucks his hands into the pockets of his sweatpants, needing to do something with his hands.

“It’s perfect. You did a great job, Gen.”

Gen  _ preens _ under the praise, and Senku feels the heat under his skin prickle again.

Gen’s heat isn’t far off.

\---

Gen wakes in the middle of the night covered in sweat and burning up from the inside out. 

He shivers, pulling the blankets tighter around him, curling in on himself to try and ease the pain of the cramps in his lower abdomen. His breathing is labored, heart pounding in his chest and thighs slick. 

His heat is  _ early. _

It has to be the fact that he's been locked up in an alphas apartment all week, practically bathing himself in Senku's scent. Speaking of Senku…

When Gen opens his eyes, he finds a pair of crimson eyes already watching him, and his breath catches in his throat. 

"Senku-chan?" Gen breathes, "What are you doing?"

Gen watches Senku's throat bob when he swallows, the light from the streetlight outside Senku's apartment casting an orangey glow on them even through Senku's thin curtains. 

"I," Senku clears his throat, tries again. "You're in heat," he says quietly, staying perfectly still. "The smell of your slick woke me up."

Gen forces an awkward laugh and averts his eyes. "Ah. Sorry. That's- that's embarrassing-"

"That's hot," Senku's words have him looking up from the blankets in front of him, butterflies tumbling in his stomach. "It's really,  _ really _ hot, Gen, and I've been laying here, trying not to lose my fucking  _ mind _ because I know you need rest, but all I can smell is your slick and I-" Senku inhales shakily- through his mouth- and Gen understands. 

"You're hard," he breathes. It's not a question. Gen's eyes track the movement of Senku's tongue as it drags over his bottom lip, the heat inside him growing more intense by the minute. "Senku," Gen whines, releasing the blankets in his grasp and sliding his hand across the blankets beneath them. There's barely a foot of empty space between them; it feels so close yet so far.

Senku's hand grasps his immediately, threads their fingers together and holds just shy of too tight. Senku's touch has flames licking down his fingers, his wrist, spreading like wildfire, and he's moving now, squirming closer in their nest, desperate to touch- to  _ be _ touched- he needs-

"Shh shh," Senku croons in Gen's ear, wrapping his arms around Gen and holding him tight to his chest, and Gen hadn't even realized he'd been whining until he stops, "I've got you." Senku's voice is low and funneled directly into Gen's ear- it's not fair how weak it makes him.

"Please, Senku-chan," Gen pants, arching, rolling, grinding his body against Senku, "it  _ aches. _ It hurts and aches and I'm so  _ wet _ for you-" he gasps at the feeling of Senku's hands beneath his underwear, on his ass cheeks, spreading them apart with zero hesitation. Senku's hands grip and squeeze, fingernails bite into the soft skin of Gen's ass, pulling soft moans and whimpers from the omega. His boxer briefs are completely soaked, but he can't bring himself to be embarrassed at all; not with Senku's index finger sliding between his cheeks and probing at his soft, puffy entrance.

Senku slides one finger into Gen's hole and groans when he finds no resistance. A second and third enter just as easily, fingers twisting and spreading curiously as Gen pants and gasps against Senku's bare collarbone. The heat haze has settled over him, and he feels drugged; he's hot all over, head foggy and body heavy. Senku's left hand still has a tight grip on his asscheek, keeping Gen spread open as he works in a fourth finger. Senku's fingers find Gen's prostate, and all it takes is a few swipes over the swollen nub for Gen to come in his underwear, eyes rolling back and toes curling in the sheets beneath them.

"Oh god-" Gen pants, nails digging into Senku's chest- trying to drag him  _ closer- _ trying to shove him  _ away- _ "oh fuck- oh Senku  _ please-!" _ Gen's body jerks, pleasure-pain jolting through his body as Senku keeps rubbing, pressing, watching him hungrily. "Nonono- I just came-" he whines.

It hurts, but it feels so  _ good _ and Gen can't take it- his body is too weak from the rush of his first heat fueled orgasm to shove Senku off, but he doesn't think he would even if he could- 

Senku's lips find his, swallowing his cries and desperate pleas-

And when Gen comes a second time in less than five minutes, he sobs, tears building at the corners of his eyes-

"So good for me," Senku praises as he rolls Gen onto his back, fingers finally slipping free of Gen's soaked hole.  _ "Fuck, _ Gen," he groans, "you're so good for me."

Gen watches, transfixed, as Senku brings his digits up to his face, crimson eyes inspecting the slick on his fingers for a brief moment before slipping two into his mouth and Gen  _ whines. _ Senku locks eyes with Gen as he sucks on his first two fingers, tongue diving between them and around, leaving nothing behind. Senku pulls the newly clean fingers out of his mouth and licks the remainder off his lips.

"Wanna taste?"

"Yes!" Gen nods eagerly. He opens his mouth, expecting Senku to slip his two other fingers in, but Senku brackets Gen's head with his elbows and shoves his tongue into Gen's mouth instead. Gen throws his arms around Senku's neck as they kiss, and it's hot and wet and Gen's sticky sweet slick tastes like nectar and he's  _ floating _ right now. 

Senku's chest is vibrating against Gen's own- he's growling. Senku is rutting against him, and Gen needs more than just their cloth covered erections brushing together.

"Senku please," he slurs as soon as the kiss is broken. "I want you to fuck me- to breed me-" and that's all Senku needs to hear, apparently, because he snarls against Gen's lips, nimble fingers going to work tugging their underwear off. Gen lifts his hips as best he can, trying to make it easier for Senku, and the minute both of their erections are free, Senku rises up onto his knees.

Gen blinks up at Senku, chest rising and falling heavily, and watches as Senku positions Gen's pliant body the way he wants him before lining himself up. Senku's hair hangs loose around his face, only intensifying the shadows being cast by the streetlight, eyes heavy lidded and dark with lust. Gen only has a second to admire Senku's beauty before Senku is breaching him, pushing into Gen's oh so wet heat and making Gen's eyelids flutter shut.

He's not sure how much time passes between when Senku first pushes into him and when Senku finally knots him, teeth sunken into the soft skin of Gen's collarbone; the concept of time is carried somewhere far, far away and Gen loses himself in Senku's scent, his hands, his bitten off curses and murmured praises of "Just like that, Gen- so good, so good- such a good omega for me- so tight and  _ wet-" _

Gen mewls and arches and writhes; Senku's back will be covered in marks by the end of the week, but the alpha will wear them with pride, Gen knows. Gen's usual filter is gone, and it only serves to egg Senku on as he begs and pleads for Senku to fuck him- to knot him- to  _ breed him- _

When Senku's knot finally locks them into place, Gen nearly screams, back arching sharply off the floor as his untouched cocklet spurts watery come all over his tummy. Senku's knot is hard and hot and huge and Gen can't stop squirming on it, milking the alpha. The fog lifts a bit with Senku's knot inside him, enough for him to talk Senku into rolling them into a more comfortable position, but with the shift, the heat haze comes rushing right back, and Gen finds himself swirling his hips as he sits atop Senku, grinding the alpha's knot against his prostate and sobbing as he works himself through another overstimulated orgasm.

When he finally collapses against Senku's chest, he feels completely and totally rung out. His eyelids feel heavy, and sleep is calling his name. Senku is carefully pulling the blankets up over their conjoined bodies, knot still buried deep inside the omega, and Gen just needs a little rest before the next bout.

God, the next bout?

Gen isn't sure how  _ he's _ gonna survive the rest of the week.


End file.
